


My Little Brother's Best Friend

by DamnItMish



Category: Supernatural
Genre: Alternate Universe - Childhood Friends, Alternate Universe - High School, Alternate Universe - Human, Awkward Kissing, Awkward Romance, Awkwardness, Drunk Sam Winchester, Fluff, Friendship, M/M, Protective Dean Winchester, Romance, Teen Romance
Language: English
Status: Completed
Published: 2020-08-02
Updated: 2020-08-02
Packaged: 2021-03-05 19:35:48
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,830
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25660729
Author URL: https://archiveofourown.org/users/DamnItMish/pseuds/DamnItMish
Summary: Sam makes a new friend. Castiel and Dean's relationship starts out rocky at first but soon they become unusual friends and maybe even more?Dean and Castiel have a one year age difference. Sam and Dean have a two year age difference.
Relationships: Castiel & Dean Winchester, Castiel & Sam Winchester, Castiel/Dean Winchester
Comments: 4
Kudos: 102





	My Little Brother's Best Friend

**Author's Note:**

> I watched The Edge of Seventeen and The Kissing Booth for the first time yesterday and couldn't stop thinking about the concept. So, here we are. I could definitely imagine writing some more OneShots in that Universe. Let me know what you think :)

The first time Sam brought his new best friend home was back when he had just started middle school a few weeks before.

"Mom?" Dean heard his little brother call out right after he heard him shut the front door "Dean?"

"I'm here, Sammy," Dean answered and stood up from where he was currently sitting in front of the living room TV "Mom is still at work. She told me she'd be working late tonight," Dean explained as he made his way over to his little brother who was still standing in the hall of their little apartment. That's when Dean saw Castiel for the first time. He stood there, visibly uncomfortable with the situation that was playing out around him "Oh, hi," Dean greeted him with a little wave "I wasn't aware we had a visitor," Dean said and threw an accusing look to his brother.

“I’m sorry, I forgot to tell you,” Sam said his tone light and furthest from apologetic “This is Castiel,” he gestured at the boy with the messy black hair standing next to him “He is in some of my classes and we share a lunch period,” Sam told Dean. Dean wanted to be mad but he really couldn’t with Sam seeming actually happy coming home from school for the first time since starting middle school.

“Hi Castiel,” Dean greeted the boy and got an awkward smile in return “I’m Dean. I’m Sammy’s big brother,” Dean heard Castiel mumble something but couldn’t quite make out what it was. The boy’s voice was too quiet “Are you guys hungry? We have some leftovers in the fridge,”

Sam immediately rushed over into the kitchen. Castiel just kept standing there, seemingly stuck in the same spot.

“Sam, how about you don’t just abandon your guests?” Dean called after him and gestured for Castiel to follow Sam into the kitchen “Just follow my brother. He has no manners,” Dean joked.

Castiel did what he was asked to do and followed Sam into the kitchen. Sam was already heating food up in the microwave as Castiel entered the room, Dean following close after.

"How old are you, Castiel?" Dean asked and leaned against the kitchen counter.

“I’m twelve,” was what Dean guessed he said. He wasn’t too sure though as the boy was still talking too quietly to be a hundred percent sure.

Sam cleared up his doubts though as he explained “Castiel is a year older than me. Isn’t that cool? Having an older friend is super cool, right?” Sam rushed out the words, clearly excited.

“I’m thirteen-” Dean said and got interrupted by Castiel.

"I had to do the first grade twice," this time Castiel spoke a little louder but rushed his words out as well. While in Sam's case Dean could tell he rushed the words out due to excitement, he wasn't too sure what caused it in Castiel's case. He assumed the boy was nervous though as he caught a glance of him fidgeting with his hands just seconds earlier.

“He didn’t speak much,” Sam took over Castiel’s explanation once again “That’s why he had to redo first grade. His big brother told me before dropping us off. What’s his name again?” the last sentence was obviously addressed at Castiel.

“Gabriel,” Castiel answered, this time a little more confident than before and his voice therefore just loud enough and steady.

“Yeah, that’s right. Gabriel. He picked us up from school and then dropped us off here,” Sam said as he got the food out of the microwave “He is sixteen. He got a driver’s license. Isn’t that cool?”

“Super cool," Dean nodded and couldn't help but smile at how excited his brother was about every aspect of the life of that kid "Are you two going to be okay on your own? I will be just down the hall in my room."

“Of course,” Sam reassured him.

“Nice to meet you, Cas,” Dean gave the two of them one last nod before leaving the room.

“He called you Cas. That’s actually not a bad nickname,” Dean could hear Sam trailing off as he went down the hall to his own room.

* * *

After that day Dean saw more and more of Sam's new friend. Castiel was around all the time and when he wasn't around Sam rambled about whatever the two of them had gotten up to that day. His Mom loved Cas too which basically meant everyone talked about Castiel all the time. Dean thought it was very strange due to the fact that the boy barely talked himself.

Sam immediately protested when Dean brought it up at the dinner table about a year after he met Castiel "He does talk to me and Mom," Sam said and crossed his arms across his chest in a very stubborn matter "Maybe if you were nicer to him, he would talk to you too," Sam said in an almost accusing tone.

“I’m always nice to Cas,” Dean said, very aware of the fact that he sounded just as stubborn as his little brother.

“Apparently you aren’t. If you were he would talk to you,” Sam argued and rolled his eyes at his older brother.

“Sam, it’s not nice to roll your eyes,” their mother warned “And Dean is very nice to Castiel. I have seen it. You probably have seen it too,” Mary said.

Dean watched as Sam avoided his gaze by letting his eyes wander to his half-eaten meal in front of him and barely heard Sam mumble "Maybe..."

“Maybe you three could spend more time together,” Mary suggested and gave Dean a pointed look.

“Mom,” Dean sighed, doing a poor job of hiding his irritation “I’m going to High School now. I’m not going to spend my time hanging out with my baby brother and his mute best friend,” this time it was Dean who rolled his eyes.

“Well, then you can’t complain about the fact that he doesn’t talk to you,” Mary argued with a shrug “Also, I saw that eye roll and I don’t appreciate eye rolls from you either, Dean,” she said and gave Dean another pointed look.

“He also isn’t mute,” Sam mumbled into his food “We had already established that.”

“Okay, calm down,” Dean chuckled “I didn’t mean to offend your boyfriend.”

“He’s not my boyfriend,” Sam said and threw a pea at Dean without any warning.

“Boys! I feel like I’m eating dinner with apes,” Mary said and raised her voice just enough to intimidate the both of them into silence.

Both Dean and Sam mumbled a quick “Sorry, Mom...” before Dean changed their topic of conversation.

* * *

The first time Dean actually had an exchange with Castiel that was longer than a few sentences was almost half a year later. Castiel was having yet another sleepover with Sam at their house during Chrismas break. Dean was in the kitchen fixing himself some sandwich to eat when Cas entered the room.

“Oh, I’m sorry. I didn’t realize someone was still up,” Castiel said and turned around as abruptly as if he had just seen Dean naked or something.

Dean couldn’t help but chuckle about that “No, it’s fine. You don’t have to leave,” he reassured him and watched as Cas slowly turned around and gave him a shy smile. Their conversation almost ended at that but Dean caught a quick glance at the clock and couldn’t help but ask “What are you doing up so late anyway? Is Sammy still up?”

“Uhm, no. He fell asleep half an hour ago,” Cas said and made his way over to the cupboard to pull out a glass “I couldn’t sleep. So, I decided to get a glass of water,” Cas explained. His voice growing more confident with every passing word.

“We could- uhm- heat you up some milk?” Dean suggested not exactly sure how he was the one stumbling over his words now “That always helps me if I can’t sleep,” Dean said and shrugged.

“I don’t want to be any troub-” Cas said and shook his head. Dean interrupted him before he could keep talking.

“No trouble at all,” Dean reassured him and got another shy smile from his brother’s best friend “You would do me a favor actually,” Dean said and watched Cas face scrunch up in confusion “I usually don’t have company for my midnight snacks. Would be nice to try it out.”

Cas shrugged at that “Alright. I guess it couldn’t hurt,” Dean started springing into action as soon as Cas said it and started heating up milk. A silence started settling between them, Dean wasn’t sure if it was an uncomfortable silence or not.

Cas seemed to be pretty sure it was an uncomfortable silence as he seemingly rushed out the next best thing he could think of to break it, "I always thought you didn't like me," it almost reminded Dean of the first day Cas visited and told him about redoing first grade. The flashback led to Dean needing a bit more time than usual to respond.

He felt bad for needing such a long time to form a response as he saw Castiel starting to fidget once again. It was one of the things Dean did pick up on in the time he had known the boy. Castiel got fidgety whenever his nerves got the best of him. Dean also felt bad for what the boy said "I'm sorry if I made you feel that way," Dean told him "I certainly didn't mean to. I do like you, Cas," Dean reassured him, "I like everyone who makes my brother feel as comfortable and happy as you make him feel," Dean said and watched Cas face fall after the first few words but also saw it twisting back into a smile when he said Cas made his brother happy.

"That's a relief," Cas said and let out a relieved sigh, almost as to highlight his words. Castiel paused for a few seconds, probably to think of what to say next before asking "How is High School going for you?"

Surprised about the question Dean’s eyes widened, “Uhm- It’s- you know?” Dean stumbled once again over his own words. Castiel looked at him with a clear confusion written on his face which made Dean's cheeks heaten up “No, you can’t know obviously. Because you’re still in middle school,” Dean said and followed it with an awkward chuckle “High School is going fine,” Dean said, mostly to avoid stumbling over his words once again and put the now heated up milk in a cup and in front of Cas.

“Do I sound as pathetic as you just did every time I stumble over my words?” Cas said and smiled at Dean as what some would almost call smug.

“Shut up,” Dean mumbled but couldn’t help but smile and roll his eyes fondly at the boy making fun of him.

Cas smiled back at him as Dean took the first bite of his long-forgotten sandwich.

"How long did you and Cas talk last night?" Sammy asked as he came out of his room the next morning "Cas refuses to get up because you guys were up so late," Sam said, the annoyance clear in his voice.

Mary who was standing in the kitchen next to him raised an eyebrow at Dean. Dean couldn’t help but awkwardly rub his neck as his two family members watched him with curious eyes.

“I don’t know, Sammy. I wouldn’t have needed to talk to him if you hadn’t fallen asleep and left your guest to his own devices,” Dean said, his tone accusing.

Now it was Sam’s turn to blush “I was tired,” he mumbled but caught himself quickly “Don’t distract from the topic at hand. We told you he would talk to you if you tried hard enough.”

Dean rolled his eyes before leaving the kitchen, “I’m going to follow his lead and go back to sleep now,” he announced.

* * *

Their one late-night conversation escalated to something close to a routine they now had. Every time Cas slept over, Dean would now stay awake until Cas finally shuffled out of Sam's room. They also moved their conversations from the kitchen to the living room couch. Besides those conversations, they still barely interacted. Dean wasn't sure what the reason behind that was. He assumed it had something to do with Cas being shy and the confidence being tired could give people sometimes. That was until one particular late-night conversation during the summer before Cas and Sam's freshman year of High School.

“Do you like High School?” Cas asked and made himself more comfortable by curling up opposite of Dean on the couch.

“I guess,” Dean hummed and shrugged “It’s harsh but having friends makes it a lot more bearable,” Cas nodded in understanding.

“I never met your friends,” Cas said casually.

“You would like them,” Dean said and smiled at the thought of Cas meeting his friends “Charlie is just as nerdy as you guys are. She loves all the nerd shit you are into,” Dean started explaining his reasoning behind his thesis “Sam loves her-” Cas interrupted before Dean could finish saying what he meant to say.

“Sam met your friends?” Cas asked and Dean could clearly see the hurt in the other boy’s eyes.

“Uhm, yeah. He’s my brother,” Dean said and couldn’t help but be confused, “Don’t get me wrong, you are here a lot but you’re not here all the time and therefore not exactly my brother,” Dean tried to explain “There is also the fact that you barely talk to me when it’s not the middle of the night,” he casually added.

Cas eyes widened and Dean watched as Cas started to shuffle uncomfortably in his seat. A silence settled between the two. Castiel was once again the one breaking the silence “I’m not good at talking to people first. I can hold a conversation just fine but starting one still makes me nervous,” Castiel gave Dean the explanation he so desperately wanted to hear ever since their midnight talks had started.

“Did I really never start a conversation with you during the day?” Dean said the doubt clear in his voice.

“Not really," Cas shrugged and visibly relaxed back into the couch, "You asked me how I'm doing a few times but that's code for "I have nothing else to say so let's pretend we care about each other". So I never really answered honestly," Dean could feel his stomach turn at the thought of Cas not knowing he cared about him.

“For future reference, I do care about you. I'm not pretending," Dean said and took a hold of Castiel's hand that was settled between them on the couch. Dean wasn't sure why he took Cas hand and he also didn't know why his heart suddenly started racing but he fought the urge to let go despite all that.

Cas eyes were focused on their intertwined hands as well and he saw the other boy swallow nervously “I can try to talk to you more too during the day,” Cas said in a low voice.

Neither of them spoke for a while. They just looked at each other and their faces were each covered by a gentle smile. That was until Dean cleared his throat and let go of Cas hand "We can watch some shitty High School TV Show if you're worried about High School," Dean suggested "And I could point out the inaccuracies," he said and grabbed the TV remote that was lying on the coffee table in front of them.

Cas simply hummed in approval.

Dean got woken up the next day by hushed voices "It's like seeing bigfoot," Dean recognized Sam's voice "They always talked about having conversations in the middle of the night but I never thought I'd see proof," he heard his mother chuckle as a response.

"Don't wake them up, Sweetie," his mother warned his younger brother "We don't know how long they stayed up," she reminded him. Dean assumed that was the point where she led Sammy out of the room as his voice got quieter as he responded or Dean was simply falling back asleep he wasn’t exactly sure.

* * *

Things progressed quickly from thereon. Not only did Dean and Cas start having conversations even when it wasn't the middle of the night as the new school year started but Cas quickly felt comfortable enough to barge into Dean's room and demand his immediate attention every time Sam wasn't home from soccer practice yet. It also led to Cas warning Dean beforehand every time he and Sam planned on going to a High School party so their paths wouldn't cross at those particular parties. Dean didn't really understand why Cas didn't want them to cross paths at parties but he just told himself that Cas must have his reasons and tried not to take it personal. That was until the end of Sam and Castiel's freshman year at High School.

Cas had just turned sixteen and gotten his driver’s license which led to him driving the two of them home one night and Sam drunkenly stumbling through the apartment.

“You’ve got to be kidding me,” Dean sighed as Sam rushed into their shared bathroom to throw up.

“I’m so sorry, Dean. I shouldn’t have let him drink but I was distracted-” Dean cut Cas off.

“What the fuck would ever be more important than Sammy?" Dean yelled but immediately felt bad when he saw Cas flinch and take a few steps back. Dean tried to calm down and lowered his voice accordingly "You didn't drink, right?" Dean asked in a low voice and knelt next to his little brother who was still throwing up.

“No, of course not," Cas mumbled. His voice a lot quieter now and Dean immediately recognized Castiel's nervous fidgeting. He hadn't seen Cas be this nervous since the night when Dean had held his hand. Dean swallowed roughly at the thought of that night. Nothing else happened but it still amazed Dean he didn't start identifying as bisexual right then and there. On the other hand, having your little brother's best friend be your gay awakening would be much more embarrassing than Dr. Sexy.

"I will never drink again," Sam heaved out, his head still over the toilet, and with that, he successfully interrupted Dean's thoughts.

“I sure hope so, buddy,” Dean said and gently rubbed circles into his brother’s back “Are you feeling any better now?”

Sam just hummed in agreement and proceeded to lie down on the bathroom floor.

"Are you sure, you want to stay here? You do have a very comfortable bed, you know?" Dean said and started ruffling his brother's hair.

“If I move I will throw up again,” Sam simply said before his eyes fell shut and he started snoring.

Dean let out a sigh of relief, flushed the toilet, and sat down on the bathroom floor. He now remembered Cas was probably still there and turned around to look for him. Cas was indeed still there. He was still standing in the exact same place Dean had moved him to with the yelling. Castiel looked absolutely mortified.

“I’m sorry for yelling,” Dean said to him and successfully grabbed Castiel’s attention “I shouldn’t have yelled at you. You did nothing wrong,” Dean gestured for Cas to sit next to him as he said that.

Cas obediently followed Dean’s request and sat down right next to him. Maybe even a little closer than Dean would have expected.

“What did you get distracted by?” Dean asked, mostly as a way to get the conversation started and watched Cas fidget where he just sat down.

“It was a pool party," Cas said in a way that made Dean feel dumb for not understanding what exactly he meant. After a quick pause and the probably all too visible confusion on Dean's face, Cas carried on "Most boys were shirtless. I like looking at shirtless boys," Cas said, sighed in defeat, and hid his face in his hands.

“Oh," was all Dean could get out as the realization of Cas liking boys hit him. Again should have been an obvious fact after the hand holding thing but Dean seemed really slow when it came to his brother's best friend.

“I know, that isn't an excuse but I swear I wasn't even gone that long," Cas rushed out and looked up at Dean with pleading eyes "I just went to the pool for a few minutes and when I came back Sam had downed more than a few beers."

“Why would Sam do that?” Dean asked. He had never pegged Sam for the type to be a rebel and drink alcohol just for the sake of it.

“His girlfriend broke up with him this afternoon,” Cas said and shrugged.

“Sammy had a girlfriend?” Dean whisper yelled. Cas just nodded his head “You storm into my room at least three times a week and you conveniently forgot to tell me that?”

“I didn’t forget to tell you about Sam’s girlfriend,” Cas said and scrunched up his nose in confusion “I withheld that information on purpose because Sam asked me to,” Cas deadpanned.

"You're a weird guy, Cas," Dean said and chuckled. He couldn't even be mad at Cas after that explanation. Besides, there was something more urgent to discuss right now anyway "So, you're into guys too, huh," Dean gave Cas a smug smile.

“Seems like it,” Cas said and rested his head on Dean’s shoulder. Dean felt his heart skip at the gesture. Dean turned his head to kiss Castiel's forehead.

Cas on the other hand seemed to have other plans as he lifted his head off Dean's shoulder immediately after the forehead kiss and just stared at Dean for a few long uncertain seconds before awkwardly crushing his mouth into Dean's. Cas applied too much pressure at first which made the experience almost painful however Cas started to relax once he felt Dean lean into the kiss and kiss back. Suddenly it felt like Dean’s stomach was having a field day as a funny feeling settle deep inside it. They kissed until they were both panting and in desperate need of air.

“Fuck,” Dean sighed and chuckled awkwardly “I can’t believe our first kiss will always have happened in a bathroom that smells like vomit next to my passed out drunk little brother.”

“I’m more worried about what Sam and your Mom are going to say,” Cas said, the fear suddenly very real in his eyes.

Dean pecked his lips really quickly with the hopes to reassure him "My Mom is going to set some "keeping the door open" rules and Sam will get over it eventually," Dean shrugged before kissing Cas again.

"Yeah, you're right," Cas sighed against Dean's lips before pulling on Dean's shirt to pull the boy even closer.


End file.
